Pneumatic hammer



my n, um. www@ A. BAILLY PNUMATIC HAMMER Filed Dec. 22. 1.921 2Shneta-Sheet 1 Maly l 1924. M4995@ A. BAILLY PNEUMATIC HAMMER Filed Dec.22. 1921 2 Shasta-Sheet 2 F11 q. j.

Patented July l, 1924.

ARMAND BAILLY, '0F PARIS, FRANCE,

PNEUMATIC HAMMER.

To all whom t may concern v Be it known that I, ARMAND BAILLY, citi- Zenof the Republic of Switzerland, and resident of Paris, France,(post-office address 46 quai Henri IV), have invented new and usefulPneumatic Hammers, which impro-vements are fully set forth in thefollowing specification.

This invention relates to pneumatic hambers, its object being the.provision of improved means or devices permitting normal working of thereciprocatory impact element or piston, and instantaneous stoppage ofsaid element as soon as the tool, for any reason, becomes displaced withrelation thereto.

An embodiment of the invention is illustrated in the accompanyingdrawings, in which: j

Fig. 1 is a sectional view of oneform o the invention showing the use ofa `device for eifecting instantaneous stoppage of the piston in theevent of the tool becoming Idisplaced; in this gure, the piston is shownat the end of it-s normal outward movement.

Fig. 2 is a view similar to Fig. 1, showing the piston as having movedbeyond its normal outer position.

Figs. 3 and 4L are views corresponding toiv Figs. 1 and 2, respectively,but showing the preferred form; l j

Referring more particularly to Figs. 1 and 2, the implement is shown asycomprising a reciprocatory impact element or j piston c disposedwit-hin a cylinder and operated by a suitable motive fluid, in thisinstance compressed air. The cylinder b terminates at its rear or innerend in an operating handle a and is provided intermediate its ends withan inlet f for the motive fluid which is supplied from any desiredsource, the inner wall of the cylinder being bored at the opposite sidefrom said inlet to form a by-pass b-y The rear end plate or head z' ofthe cylinder, which is clamped or otherwise secured betwen the cylinderend and the handle, as shown in Fig. 1, is formed with a lateral tube kwhich projects axially and forwardly into the cylinder; and the bore nof this tube opens at its free front end into the cylinder and at itsinner or rear end into centrally-intersecting passages or conduits oformed internally of head c'. The free outer ends of the conduits o openinto an exhaust conduit p formed internally of the handle c; saidexhaust conduit p, in turn,

Application led December 22, 1921. Serial No. 524,278.

through the central portion of the rear face atmosphere through of thepiston opens an axial socket c3 whichA is ofV a size and shape toslidably receive therein the exhaust tube 7c during the movements of thepiston. A passage c leads axially from the inner end of the socket andopens through the front or outer end of the piston. Consequently, thepiston may thus be regarded as bored from end to end and the passage cserves, as will be apparent, to permitthe flow of the air leaving orentering the closedspace 1 (Fig. l).

As previously stated, means are provided for effecting instantaneousstoppage of the piston in the event that the tool, from any cause, hasbecome displaced with relation to the piston. ln the arrangementillustrated in Figs. 1 and 2, this object is effected by lmerelyproviding the piston with a rearward axialprojection B through which thesocket c3 opens; this projection being formed with lateral ports orapertures C, and the 2 exhaust tube with corresponding ports orapertures A.. l

Starting with the piston at the end of its normal left-hand or outwardstroke, as represented in Fig. `1, the operation is substantially asfollows: Air under pressure passes into lthe cylinder through inlet andfills the space 'g between the shoulder or enlargement d and theadjacent cylinder wall, acting on the shoulder to drive the pistoninward or rearward toward the right. As the piston continues its inwardmovement, the exhaust tube enters further and further into the socket c3and communication is ultimately established between space g and thelil() soon as the piston, in its outward or right-- ward movement,brings its ports or apertures C into registration with the ports orapertures A in tube 7c exhaust takes place at the right-hand side of thepiston through said registering ports, said bore and the parts o-p-Q,the pressure on the left-hand side of the shoulder el predominates, andthe piston again movesleftward, and soon.

As above explained, the two sets of ports or apertures referred to arebrought into regis-- tration when the piston reaches the end of itsnormal forward or outward movekment, as indicated in Fig. l, and the airin the rear or inner part of the cylinder behind the piston then exhaustto the atmosphere through the parts C, A, n, 0i, p, g. But if, from anycause, the tool has been displaced forward, the piston willv continueits forward movement beyond its normal limit and will reach the positionillustrated in Fig. v2. In that position, the apertures C land A are outof registration, exhaust to the atmosphere'- is shut off and thecompressed air. entering the cylinder through inlet f acts, against therear= face Z of t e piston, with the result that the latter isimmediately stopped and held stationary. Consequently, any displacementof the tool as above described willautomatically effect vinstant andabsolute stoppage of the' piston without 'any directv passing of the airinto the atmosphere, as' is generally the ease with the apparatusheretofore used.

In the preferred construction represented i in Figs.- 3 vand 4, theapertured projection B on the pistonand-the apertures yA in the exhausttubel are omitted; and in place of the said apertures A, the tube isformed adjacent its forward end with a circumferential groove or recessA which produces immediately in advance thereof a head or collar D ofthe same/ diameter as the tube itself.v In place of the projections B,the socket in the piston is enlarged intermediate its ends to form achamber C; the portion B of said socket immediately in front of thegroove having substantially the saine diameter as the head or collar Donl the exhaust tube. ViIhen the parts are in Fig. 3 position, whichcorresponds lto that illustrated in Fig. l, the air in the rear part of.the cylinder, behind the piston, will pass through the groove A andtheportion B of the socket into the chamber C and thence t0: the atmospherethrough the par-.ts n, o, p, q, as before; it being-understood that theformation of a chamber, such as C', of

greater diameter and length than head D is essential in order to aermitthe air entrance through A and to pass around said head and to flow intothe free end of bore n. Cn the other hand, when displacement of the tooloccurs and the piston moves beyond its normal terminal position intoFig. 4 position, corresponding to the position in Fig. 2, then the headD of the tube will be disposed within the portion B of the socket andwill shut ofi' entry of air into chamber C and its escape therefrom tothe atmosphere. In this position, the inlet f will beuncovered andcompressed air will enter and fill the cylinder, causing absolutestoppage of the piston.

I claim as my invention:

l. In a pneumatic hammer, the combination of a cylinder provided at itsrear end with a stationary axial exhaust tube; and a reciprocatoryimpact piston in the cyl-- inder having a socket in its rear end toreceive said tube and a passage leading from its front end into saidsocket; the piston and exhaust tube having openings adapted to coact inestablishing temporary communication between the cylinder and theatmosphere and thereafter to interrupt such communication and therebycause the automatic stoppage of the piston.

2. In a pneumatic hammer, the combinationof a cylinder having anoperating handle at its rear end, and an axial exhaust tube fixed atsaid end and communicating at its rear end with outlet passages formedthrough said handle, said tube projecting forwardly into said cylinder;and a reciprocatory impact piston in said cylinder having an axialsocket in its rear end to slidably receive said tube and an axialpassage opening at one end through the front end of the piston and atthe other end into said socket; said piston and exhaust tube havingmeans for establishing temporary communication between the cylinder andthe atmosphere, said means thereafter interrupting such communication soas to cause the alltomatic stoppage of the piston, and said cylin'derhaving an inlet in its side wall for the motive fiuid and a channel insaid wall for by-passing the fluid from one side of the piston to theother.

In testimony whereof I have signed this specification.

. ARMAND BAILLY. Witness:

CHARLES LEON LoIsEL.

